Not certain, but it sounds lke someone has been tinkering with the workgroup file on the client site and has altered the permissions on the systems objects.
First off I'd suggest they go back to the last known good workgroup file, and try to see if that clears the fault. I'd try to examine the workgroup fle to see who,or what usergroups are remaining as administrators.
There are other techniques to try to re-create the permissions, but I can't remember at present, I think youcan flush misset priveleges using by copying all the objects to a new db.
Will have to have a look in the Access Developers Bible when I get back to work....